Business forms, paper, and many other products are conventionally shipped and stored in two piece cartons having a carton body and a top, both of cardboard. Since it is highly desirable for the carton lids to be reused in such cartons, the carton lid is typically secured to the carton body by plastic straps. This is an expensive procedure, however, since there is a substantial investment in automatic strapping equipment, since the plastic straps are relatively expensive, and since there are significant maintenance costs associated with the automatic strappers. Therefore, it is highly desirable to provide a carton with a reusable lid that may be shipped without plastic strapping, while still securely maintaining the carton contents.
Further, in conventional corrugated cartons, during shipping and handling varying amounts of weight and momentum are applied to the carton. This has led many users of cartons to build higher cost and higher strength corrugated paperboard cartons in order to maintain a rigid box of unchanging depth. However, if the box is able to flex to accommodate varying amounts of weight and momentum that are applied during shipping and handling, lower cost paperboard may be utilized, yet the carton will retain its integrity and uniformity throughout its useful life. This is especially desirable in the area of packing paper products, such as business forms, which tend to expand and contract over time and to settle after initial packing since voids are common in the depth dimension.
According to the present invention, both of the above mentioned problems are solved in a simple and effective manner. According to the present invention the expensive strapping equipment necessary for most commercial carton packaging systems is eliminated, the cost of materials for packaging are greatly reduced, and since the equipment utilized to effect packaging according to the invention is much less expensive with a much simpler construction, equipment maintenance costs are substantially reduced. For example, according to the present invention the apparatus for effecting packaging can be about one-fifth the cost of conventional strapping equipment, while the operating cost per thousand cartons is less than one-tenth, and almost no maintenance is required. Also, according to the present invention 125 pound, 150 pound or 175 pound test corrugated paperboard may be utilized instead of 200 or 275 pound test corrugated paperboard typically used, and without the need for corrugated or Styrofoam.RTM. filler pads that are typically utilized in conventional cartons.
According to the most basic aspect of the present invention, the above highly desirable results are achieved by constructing a cardboard carton lid in such a way that it has elongated side sections or panels, with a bottom portion thereof attached by adhesive--or other fastening means--to the side walls of the carton body. First and second parallel lines of weakness are provided between the top and bottom edges of the carton side panels, the carton flexing along those lines of weakness during handling, the flexing action allowing lower weight paperboard materials to be utilized. The carton may be easily opened by removing the strip between the lines of weakness, after the strip removal the carton lid being essentially the same as a conventional carton lid, and readily reusable. During packing of the carton, the carton will be filled above the top of the carton body (e.g. by business forms stacked an inch above the carton top edge), and a compressive force will be applied to the carton to reduce void volume prior to adhesion of the side sections to the carton side walls. This, combined with the flexing action about the lines of weakness, allows the carton to retain its integrity and uniformity throughout customer use, and improves protection for the product packaged and the customer perception of product quality.
According to one aspect of the present invention, a cardboard carton lid is provided which comprises a top panel; first and second end panels each having a top edge and bottom edge, and extending generally perpendicular to the top panel and connected thereto at the top end of each, the bottom edge of each spaced a first distance from the top panel; at least one side panel having a top edge and bottom edge, and extending generally perpendicular to the top panel and connected to the top panel at the top edge thereof, the bottom edge spaced a second distance from the top panel; a first line of weakness formed in the side panel parallel to the top edge and between the top and bottom edges thereof, and a second line of weakness formed in the side panel parallel to the first line, and between the bottom edge and the first line; and the spacing between the second line of weakness and the bottom edge of the side panel being sufficient to define a bottom, fastening section of sufficient dimension to be securely attachable to a carton body. The lines of weakness preferably comprise perforations, and a removable strip is provided between the lines of weakness. Means are also provided for facilitating grasping of the removable strip to allow tearing of the side panel at the perforations so that the bottom, fastening section of the side panel is detached from the rest of the lid. Such means preferably comprise a die cut blank formed in the strip, and die cut lines adjacent the blank and forming a part of the lines of weakness, the die cut lines extending at a slight angle with respect to the perforation so as to provide an enlarged grasping portion of the strip therebetween. The carton lid may be formed of 175 pound test, or less, corrugated paperboard, as opposed to conventional 200 pound test corrugated paperboard.
A cardboard carton is provided according to the invention which has a body with opposite side and end walls, a closed bottom, and an open top defined by a top edge. A lid--as described above--is fastened to the carton body, by fastening means (e.g. glue or other adhesive) fastening the bottom fastening sections of the lid to the carton body side wall. The carton is typically filled with material to be packaged--e.g. sheets of paper (for example, business forms) extending from the carton bottom in a stack up past the top edge of the carton body.
According to another aspect of the present invention, a method of packing a cardboard carton is provided which comprises the following steps: (a) Filling the carton with substantially non-deformable material to be packaged so that the material contacts the carton body bottom and extends upwardly past the top edge of the carton body, (b) Placing the lid on the carton body so that the top panel thereof engages the material extending above the carton body top edge and so that the lid side and end panels overlap the carton side and end walls, respectively, (c) Applying a compressive force to the carton lid sufficient to reduce void spaces in the material to be packaged so that the lid top panel is moved closer to the carton body top edge. And, (d) while the components are in the compressed position of step (c), affixing the relatively long lid side panels to carton body side walls without interfering with the ability of the lid to flex at the lines of weakness, so that once step (d) is completed, the carton will flex at the lines of weakness. The method preferably consists essentially of only steps (a-(d), so that no strapping is necessary to maintain carton integrity. Typically, the carton is overfilled with paper, or business forms, e.g. to a height one inch above the carton body top edge.
The method according to the invention also has as an aspect thereof not only the method of packing the cardboard carton, but reusing the carton. The carton is packed as described above, and then the lid is detached from the body by removing a strip between the lines of weakness. The lid can be removed and replaced as desired--i.e. is completely reusable--and in fact even can be used for subsequent shipping by taping the lid to the side and/or end walls of the carton body.
It is the primary object of the present invention to provide a method of packaging utilizing a cardboard carton that is as effective or more effective than conventional packaging procedures, yet significantly less expensive and/or simpler; and an improved cardboard carton and lid. This and other objects of the invention will become clear from an inspection of the description of the invention and from the appended claims.